Integrated Ecological Approach to the Management of European Wild Boar (Sus Scrofa) in Great Smoky Mountains National Park

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AN INTEGRATED ECOLOGICAL APPROACH
TO THE MANAGEMENT OF
EUROPEAN WILD BOAR (SUS SCROFA)
IN GREAT SMOKY MOUNTAINS NATIONAL PARK
MANAGEMENT REPORT NO. 3

NATIONAL PARK SERVICE

SOUTHEAST REGIONAL

UPLANDS FIELD RESEARCH LABORATORY

GREAT SMOKY MOUNTAINS
NATIONAL PARK

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LIBRARY

GREAT SMOKY MOUNTAINS

NATIONAL PARK

AN INTEGRATED ECOLOGICAL APPROACH
TO THE MANAGEMENT OF
EUROPEAN WILD BOAR (SUS SCROFA)
IN GREAT SMOKY MOUNTAINS NATIONAL PARK
MANAGEMENT REPORT NO. 3

by

Dr. Susan P. Bratton
Uplands Field Research Laboratory
Great Smoky Mountains National Park

LIBRARY

GREAT SMOKY MOUNTAINS

NATIONAL PARK

5^3.73 4-

MAR 1 0 «*

Note to the reader:

Although this paper is presented as No. 3 in the Management Report
Series of the Uplands Field Research Laboratory, it was originally
presented to the Park Service in 1974, before the Management Report
Series was started. Because the Uplands Field Research Laboratory
is continuing to receive requests for the paper, we have reprinted
it. Since Park management policies have changed in the last year,
some of the material presented here is already out of date, but the
general presentation and bibliography should be useful to reseachers,
students and managers interested in wild hogs. The bibliography has
been expanded to include more recent items and papers not discussed
in the original report.

Digitized by the Internet Archive

in 2012 with funding from

LYRASIS Members and Sloan Foundation

http://archive.org/details/integratedecologOObrat

An Integrated Ecological Approach to the
Management of the European Wild Boar (Sus Scrofa)
in Great Smoky Mountains National Park

Susan Power Bratton
Cornell university
Ithaca, New York
April 8th , 19 74

Since the Park Service Hog Control Program began in 1959, several
hundred hogs have been killed or removed from the Great Smoky Mountains National
Park. This program has, however, failed to limit the growth of the hog popula-
tion. During the period the present control program has been in effect, the
number of wild hogs in the Park has not only increased, but the hogs have
extended their range to include well over half the Park. The Park Service should,
therefore, review their policies concerning the elimination of this exotic species
and consider modifying both the control techniques employed and the type of
scientific study presently encouraged.
I. The reasons management is necessary.
A. Damage to the Park

The need for a more intensive management program is related to a multi-
tude of ecological problems presented by hogs. First of all, the proliferation
of wild swine throughout much of the Park has been extremely disruptive to certain
elements of the native flora and fauna.

Among the damages inflicted by wild boar are:
1. The destruction of wild flower areas.

Hogs rely heavily on underground parts of plants and the resulting
rooting disturbance is removing the herbaceous understory of certain forest types.
Beecn forest understory may be reduced to 2 percent of its normal cover.In the
Western half of the Park, the carpets of spring beauties ( CUyjtonia Virginica) ,

fawn lily (Ery thronium Americanum) , and wake robin (Trilium E rectum) have been
greatly reduced in both cover and the number of blooming plants (Bratton 1974).
Some of the sites most famous for these floral displays, such as the "rich, wooded
slopes. . .along the Appalachian Trail between Newfound Gap and Indian Gap" recom-
mended in Great Smoky Mountains Wildf lowers , a popular guide by Campbell, Hutson
and Sharp (1970), are still free of hogs. With the present range extensions and
population increases of the wild boar, however, this situation will eventually
change. The movement of the hogs into the forests near Route 441 and the Clingman's
Dome road will make their rooting activities far more noticable to park visitors
and may create public relations problems. Damage to well known wildf lower sites will
probably include some of those usually visited by the Wildflower Pilgrimage.

2. Reduction of individual plant populations.

The hogs actually eat certain species of wild flowers. The Turk's cap
lily (Lilium superb urn) , for instance, has edible bulbs. "A large colony of this
beautiful lily", which according to Great Smoky Mountains Wildf lowers, "appears
along the Appalachian Trail between Clingman's Dome and Siler's Bald" was selec-
tively rooted for Turk's cap bulbs in the summer of 1973, and most of the plants
were removed. The recovery potential of this species is unknown.

All together about a third of the herbaceous species listed in Great
Smoky Mountains Wildf lowers, have already been observed to be eaten, uprooted or
trampled by hogs. (Bratton, 19 74) . The list of affected species may be expected
to grow as the hog population expands and observation of hog rooting continues.
There are at least 95 genera mentioned as hog food plants in European studies which
are also found in Great Smoky Mountains National Park (Bratton, 1974).

3. Damage to tree roots and seedlings.

The exposure and death of innumerable fine roots of woody plants, accom-
panies the overturn of the soil surface during hog rooting. Field observation
indicates that certain woody roots, such as those of pitch pine (Pinus rigida)

and tulip tree (Lireodendron tulipiferia) , (Conley et al., 1973) are eaten. In
other cases, such as that of beech (Fagus grandlfolia) there is no evidence that
the cambium is stripped from the larger roots. Small roots are sometimes eaten
incidentally but a majority of the superfical fine roots are left to dry on the
soil surface.

The implications of this sort of root system damage for tree growth and
reproduction have apparently never been investigated in the United States. European
studies on both wild and domestic swine indicate selective damage to different tree
species. In one experiment with domestic hogs Bjerke (1959, cited in Forestry
Abstracts) found that pigs would bark oak and elm, whereas both young and old beech
were usually left alone. After a year of hog occupation, in the forest in ques-
tion "...there were 20-80 Beech seedlings / sq. m. in autumn 1959 compared with 1
seedling / sq. m. before." Feeding experiments indicated a preference for oak, elm
and alder bark, followed by ash and hornbeam. Hazel, birch and maple were rarely
eaten; beech was completely untouched. These results are in agreement with a
European theory that intense grazing and rooting by domestic swine over a period
of several hundred years, has altered the species composition of many European
forests in favor of beech. (Bjerke 1957, cited in Forestry Abstracts)

Wild boar should have a similar impact although their density per hectare
is usually less. In the Great Smoky Mountains, a large population of wild boar
may, over a long period of time, change the species composition in some types of
forests. In high elevation hardwood forests there is already a noticeable increase
in beech root sprouts after hog rooting. Some of the most heavily damaged sites
have the most sprouts.

4. Damage to the grass balds.

The hogs break and roll the turf under the mountain oat grass (Danthonia
compressa) , causing soil erosion and a change in the local successional pattern.
Weedy forbs such as Potentilla and Rumex usually invade the scars because the

grasses are slow to recolonize. Hogs also root under shrubs and in patches of
Rub us. These sites are reoccupied by Potentilla and semi-shade plants like
Stachyus clingmannil.

5. Soil erosion.

In the most heavily rooted sites the organic surface horizons of the
soil are throughly mixed with mineral soil from lower layers. Deprived of the
protective cover of leaf litter, these areas suffer sheet erosion and compaction.
There is little doubt that the sediment load in some creeks is increased. The
hogs' habit of rooting along stream banks and digging wallows in springs and
small creeks serves to magnify the problem. The impact of hogs on the stream
biota is unresearched, but should be of great interest, particularly to trout
fishermen.

The changes in the leaf litter and soil surface structure are a form
of habitat destruction which also affects the smaller native terrestrial animals.
Of notable importance is the adverse impact on the herpetofauna, particularly
salamanders.

6. Predation on native animals.

Hogs consume a wide variety of animal foods. They eat large quantities
of invertebrates, some of which, for instance, earthworms (Tanda 1957, Briedermann
1968, Scott 1973) and ants (Tanda 1957), are usually assumed to be beneficial to
the forest ecosystem. Other invertebrate food items are snails, mussels and
crayfish (Boback 1955, Sludskii 1956).

Eurasian studies indicate mice and other small rodents are eaten when
they are available. Briedermann (1968) found 143 mice representing two families,
Microtidae and Muridae and three genera Apodemus , Microtus and Clethrinonomys , in
102 of 181 wild boar stomachs, he investigated. He also found two moles (Talpa
europaea) . Bromlei (1964) and Sablina (1955) list moles and mice as major animal
components of the hogs diet. Sablina (1955) notes that wild boar not only eat

small rodents but invade their nests, devour their young and break into their
winter stores. The latter type of behavior has important consequences for squirrels
and chipmunks in the Great Smoky Mountains.

Hogs sometimes attack larger mammals. An excessive population of wild
boar is therefore, considered bad management in European hunting preserves. "It
is well known, that in a Revier with many wild boar, the hare hunting deteriorates"
(Boback, 1955). This is largely due to the consumption of young hares and rabbits
(Haber 1961, Snethlage 1967). According to Boback (1955) hogs will occasionally
kill fawns. Usually, however, big game is sick or injured before it is attacked
by wild boar.

The same principles of management also apply to ground nesting birds
since hogs eat both their eggs and their young. (Sablina 1955, Haber 1961). Boback
(1955) mentions, for instance, that "An increase in wild swine initiates a
decrease in the Capercaillie." (or Auerhahn, Tetrao urogallus) and that a high
density of wild boar is simply not compatable with maintenance of a huntable
population of this ground nesting member of the grouse family, similar to our wild
turkey in size. In Europe the boar also disturb red grouse and pheasant.

In the Great Smokies the birds most likely to be affected by wild boar
include both ruffed grouse and wild turkeys. Turkeys are not very common in the
Park (Stupka 1963) and are extremely sensitive to disruption during nesting.
Although as Stegeman (1938) points out, grouse and turkeys may benefit from in-
creased food availability through the insects turned up by hogs, the beneficial
effects of hogs are probably negatively correlated with the number of pigs in an
area. The larger the populationof hogs, the more certain the destruction of nests.

Aside from birds and mammals the hogs eat lower vertebrates - fish,
amphibians and reptiles. Both snakes and salamanders have been found in the
stomach contents of hogs shot in Great Smoky Mountains National Park. (Scott 19 73)

6

Briedermann (1968) found 6 blindworms (Anguis Vragilis) , 2 fence lizards (Lacerta
agilis) , 3 water snakes (Natrix natrlx) and 24 assorted frogs in the 181 stomachs
he examined. Sablina (1955) believes that wild boar actively seek out snakes
in the brush and that the boar are not afraid of being bitten. This agrees with
the observations of the local people in the Great Smokies who believe both wild
and domestic hogs eat all types of snakes, including pit vipers. Sablina (1955)
notes that the number of snakes in Belowesh Preserve in Poland is severly reduced
in years when the boar population expands.

The Great Smoky Mountains National Park has an interesting and well deve-
loped woodland herpetofauna and has an international reputation for its diversity
of salamanders. A large population of wild hogs is not compatible with maintain-
ing many of these native reptile and amphibian populations at their normal levels.
Habitat destruction may prevent locally exterminated species from reestablishing.

7. Competition with native species.

Perhaps the greatest competitor of the boar is the black bear. Recent
studies of bear (Beeman 19 71) and boar (Matschke 196 7, Henry and Conley 19 72, and
Scott 1973) have shown the importance of mast to both species in the fall. The
wild boar also consume herbs, grasses, berries and carrion which might otherwise
be available to bear. Black bear prey on young hogs, but this probably does
not compensate for the mast lost to hogs in the fall, especially when the hog popu-
lation is large. Boar may avoid bears as predators but Reed King, a local hunter,
reported seeing a large boar drive a young bear away from an oak stand with a good
crop of acorns.

Several other species, including deer, turkeys, squirrels and chipmunks,
also compete for mast. Deer and boar both graze sedges, grasses and herbs along
the trails and on the grass balds. The hogs also utilize animal foods, such as
insects, crayfish, amphibians, small mammals, and birds eggs which would otherwise
be available to skunks, opossums , raccootts, foxes and bobcats.

One should note that the European wild boar has many competitors in its
native range and that it has coexisted with several species of deer and bear for
thousands of years. Sablina (1955) points out that, of the plant species
utilized by both deer and hogs in Europe, in only a few cases are they consumed
by both species at the same time of year or are the same parts eaten. The brown
bear (Ursus arcticus) is well adapted to competition from wild boar and turns to
preying on hogs when the mast crop fails (Rakov, 1966). Even, in its native range,
however, an over population of boar is detrimental to other species and a well
managed preserve keeps the wild boar ppulation low.

There is in fact, no reason why a small population of wild boar could
not coexist with the larger mammals in the National Park. At Tellico Wildlife
Management area deer, boar and bear live together and each species maintains
a huntable population. A substantial portion of the hog population is killed by
hunters each year, however.

The apparent recent drop in the bear population in the Great Smokies
has been attributed to competition with hogs - a logical accusation. The hog
population must be near carrying capacity in the Western half of the Park and
the hogs are certain to dominate a majority of the food available. Local
hunters estimate hogs outnumber the bears by more than 20 to 1 around Cades Cove.
(Reed King and friends, personal communications). The continued uncontrolled
growth of the wild hog population is placing increasing pressure on the native speciej
with which it compeces for food. The harm to the bear population alone, provides
a sound reason for monitoring the hog population and artifically inhibiting its growtt

It should, in summary be obvious that wild hogs are a ubiquitous problem.
They are affecting every major plant community and many of the best known animal
species in the Park.

8

Population Dynamics.

The second major reason, after that of ecological damage, for instituting
artifical control, concerns the dynamics of the boar population itself. Obviously
food is available in the Park and the hog population is expanding. The rate of
population growth in the Park indicates the wild boar is no more limited by environ-
mental factors than it is in its native range. The question then becomes which
factors are presently limiting hog population growth and, if the Park Service
does not institute a more intensive management program, what will ultimately limit
the hog population?

The potential limiting factors include:

1. Predation.

Throughout its native range the wild boar has a variety of predators.
In the Amur territory of the Soviet Union, Rakov (19 70) found the brown bear
(Ursus arcticus) was responsible for 21.8 percent of all hog mortalities, the
wolf was responsible for 6.9 percent, the tiger was responsible for 5.0 percent,
the lynx for 1.7 percent and the leopard for .6 percent. All together predators
accounted for 36.0 percent of the animals found dead and 55.8 percent of these
were piglets. In Belowesh preserve, by contrast, the wolf is the most important
predator of hogs and hogs are the single most Important species in the wolves diet.
The numbers of hogs killed by wolves alone may exceed 10 percent of the total esti-
mated hog population and can constitute over 25 percent of the wolves diet (Gaurin
1954) .

Of the species mentioned above, only the lynx has an ecological equi-
valent in the Great Smoky Mountains. Bobcats (Lynx rufus) function as the European
lynx does by hunting and killing piglets. The black bear, on the other hand, is
a smaller, less aggressive animal than the brown bear and therefore is a less
effective predator. The wolf has been extirpated from the Park and the only native
big cat,, the mountain lion, is either extinct or very rare in the Southern

Appalachian^ Lin zey and Linzey 19 71). The wild boar in the Park is thus free from
much of the predator pressure to which it was subject in the Old World.

2. Weather conditions.

In some areas, a second major cause of mortality is freezing, which is
usually associated with starvation. (Rakov 1970). A mean snow depth of 50
cm. is, in fact, usually considered to be the major limitation of the wild boar
on the Northern border of their range in Europe (Heptner and Naumov 1966). A
frozen soil surface prevents rooting and deep snow inhibits the movements of hogs.
Bad weather in combination with a poor mast year may reduce the hog population
to extremely low levels. In Belowesh Preserve, drops in the hog population of 50
percent annually may be attributed to frozen soil and bad weather. Cabon (1958)
and Kozlo (19 70) describe in detail a combination of hard winters and poor mast
crops which dropped the population from 1166 in 1951 to 176 by 1956. Rakov (1970)
lists freezing as the most Important cause of death in the Amur territory. Severe
winter weather was blamed for 49.3 percent of the total mortalities. In Rakov's
study there were 524 deaths from all causes in January and February whereas there
were only 49 from May to September.

The climate of the Smokies is not cold enough to freeze the soil solidly
for long periods, and severe snow storms are rare at lower elevations. Weather
alone should not conslstantly limit hog population growth, although a bad storm
during farrowing In February or March may kill a large number of piglets.

3. Disease.

The European wild boar is susceptible to a number of contageous diseases
of which hog cholera is one of the most devastating. The chances of disease
outbreaks increase as the density of the population Increases. The hogs, of
course, also become more liable to parasites and disease when they are short of
food and in a weakened conditions.

10

Disease outbreaks are a common management problem in Europe. Spiecher
(1969) describes a hog cholera epidemic in Germany which reduced many of the herds
in shooting preserves to 10 percent of their original number. The disease is
usually contracted from domestic hogs or infected supplementary feed. German law
requires the "Vetinary Police" be informed of any cases because the wild boar fre-
quently manage to reinfect domestic stock.

The impact of disease in an overpopulated area can be very dramatic. In
Belowesh preserve an estimated population of 2000 hogs in the spring of 1964 was
reduced to 550 head by the end of the year because of an epidemic which began in
June (Kozlo 19 70). Note, however, that by 1966 the population had returned to
a stable size of 1250. Though a disease outbreak may relieve overcrowding,
a well established hog population will return to a healthy level within two or
three years. In a small preserve, on the other hand, a herd may be exterminated
due to health regulations.

In 1973, there was no evidence of high disease mortality in the Great
Smoky Mountains. The wild hogs throughout the whole Southern Appalachian area were
apparently free of hog cholera. Even though the likelihood of disease outbreaks
will increase as the hog population increases, epidemics should not be looked
to as the eventual solution to the "hog problem". First, the wild boar is well
entrenched in the National Park and the herds are scattered throughout many small
watersheds. Therefore, not all the hogs would be infected and the population
should recover quickly. Second, a bad outbreak of hog cholera would create im-
mediate management and public relations problems. The Park Service would have to
call in Federal disease control personnel, and would have to shoot infected animals
and dispose of the bodies. The Department of Agriculture might require that
certain areas be quarantined and that disinfection procedures be instituted. Both
of these procedures are in conflict with the aesthetic experience a visitor expects

11

in a National Park. Third, the health of the wild boar in the Park is related to
the health of other wildlife and to that of domestic stock on neighboring farms.
Aside from parasites like trichinae, hogs may contract and spread contagious
diseaseslike rabies or hoof and mouth disease. (For general references see Wetzel
and Riea 1962, Weidemuller 1964, Kerschagl 1965, and Schulze 1965)

Disease would not force the hog population to a consistantly low level
but instead would result in fluctuations and continued damage to the native biota
of the Park. Epidemics have undesirable side effects and should be avoided by
careful population management.

4. Food.

Food availability is always an ultimate limit on population growth and
in the long run will determine the carrying capacity of different habitats for
hogs. Allowing the hogs to reach carrying capacity is the least desirable way
of limiting the population because it will have the most undesirable impact on
other species. Herds of starving hogs, gobbling up every acorn, salamander,
bird's egg, and flower bulb, can hardly be considered an ideal solution to hog
population growth. Even if the Park Service decides they cannot possibly hope
to exterminate the hogs, the population should be kept well below the carrying
capacity, as determined by food resources, in order to alleviate the effects of
competition and predation on other species. A population limited by food will
cause extensive rooting damage which will probably include areas which are low
in food resources and of marginal value to the hogs.

5. Hunting by man.

Human hunting pressure is today one of the most important controls on
European wild boar throughout the agricultural regions of its native range.
Hunting has extripated the wild boar from many areas including Great Britain
and the Nile Valley and has substantially reduced the boar population throughout

12

most of Western Europe (Niethammer 1963). Range changes in recent years have
been closely related to hunting by man. (Heptner and Naumov 1966).

There are numerous examples in the literature of the effects of
differential hunting pressure. Vereshchagin (1967) states that "Hunting was the
chief operative factor in the disappearance of boar from (ancient) Christian
Armenia, a fact that is pointed up by the contemporary existence of a large boar
population in considerably drier regions of Iran and Turkey..." where the Moslem
residents do not eat pork. A more recent example concerns a steady increase in
the wild boar populations of Germany and Eastern Europe during and after the
Second World War. This has been attributed to lack of hunting and controls on
the ownership of fire arms immediately after the War. Because of agricultural
damage, the populations had to be strongly reduced. In Germany, for instance,
8784 hogs were shot in 1938-1939, and 21,157 were shot in 1957-1958 (Muller-Using
1960). In Poland, where the wild boar population was 46,500 in 1954 and 50,000
in 1955, the state game managers decided to reduce the population to 30,000 to
curb damage to crops. Through intensive hunting they lowered the population to
40,000 by 1959 (Haber 1961).

In the Great Smoky Mountains there are two types of human predators on wild
boar - one is the ranger who participates in the Park Control Program and the other
is the illegal hunter who brings his gun and dogs inside the Park boundary. The
rate at which the Park Service has removed hogs is well documented but the exact
number of hogs removed by poachers is impossible to estimate with any degree of
confidence. According to Reed King, a local farmer who was arrested for hunting
in the Park, there were about 80 hogs removed from the Park by residents of Wear
Valley and Townsend in 19 73. The most active poachers supposedly kill more than
20 hogs apiece a year. One poacher is reported to have killed 26 or 27 wild hogs
in the Park that year. This information indicates that the count of illegally
taken pigs is certainly over 100 per year and may be in excess of 300. Pig hunting

13

in the Park apparently became popular in Tennessee about 1959, the same year the
Park Control Program began, and accelerated through the 1960's.

The large number of hogs in the Park encourages illegal hunting and is
related to poaching of other species. The hunters know that the Park Service
is trying to reduce the hog population and they are perfectly aware the Park
Service has failed in this attempt. As far as the hunters are concerned they are
doing the Park a favor by shooting hogs, and they therefore, can easily rationalize
killing a deer or bear. The large hog population has also renewed interest by the
hunters' lobby in creating a legal hunting season in the Park. Their arguments
are becoming difficult to ignore, as the hogs take over more and more of the Park.

A recent crackdown on poaching, conducted by rangers in the summer of
19 73, may change the importance of illegal hunting as a control on hog popula-
tions. The dilemma is simply - if the Park moves to restrict poaching without
increasing its own control program the hog population will expand even faster;
if the Park Service does not inhibit poaching more bears will be shot. An intensi-
fication of poacher patrols should therefore parallel on intensification of hog
control. It is quite possible that poachers have exerted more of a control over
the hog population than the Park Service has. During the one year period of
Fox's (1972) study, 139 hogs were "officially" removed. Poachers probably took
at least that many and may have killed twice that number.

Legal and illegal hunting and trapping have together slowed the
colonization of the Great Smoky Mountains by hogs, but they have hardly stopped
it. Since the actual number of hogs killed by man is far greater than the number
listed in the Park records, the Park Service must not only increase the number
killed relative to the number they already take but they have to relieve the
poachers of their present share.

The swine in the National Park will never be greatly limited by native
predators and weather conditions. The choice is therefore between starvation and

14

disease or hunting by man. Starvation is undesirable because a large, collapsing
population will heavily root all available feeding sites and compete heavily
with other animal species for food. The population fluctuations which a strictly
food or disease limited population undergoes would not allow sufficient time
for the disturbed plant and animal species to recover. Control by man is
necessary just to stabilize the hog population at a moderate level. Considering
the number of hogs already removed by hunting, reducing the population until it
has a negligible ecological impact will require very intensive management.
European work, has shown that populations can be controlled and reduced by hunting.

II. Establishing control over the hog population.

A. Reproductive potential and carrying capacity.

Before beginning a control program, the managers have to know how many
hogs have to be removed to stabilize or to reduce the population. The answer is
quite complex and is a function of the carrying capacity of the Park and the repro-
ductive potential of the hogs.

Hogs have large litters and can easily replace individuals lost through
predation or disease. In Belowesh Preserve, annual Increases in population have
been as high as 178 percent (from 478 to 1325 hogs). From 1946 to 1966 over
half the positive annual changes in population were over 40 percent. (Kozlo
19 70). Similar rates have been found in the crime a where an introduced herd of 35
individuals expanded to 2100 over a period of 10 years (Kormilitsin and Dulitskii
19 72).

Reduction by hunting is somewhat like reduction by disease - if the
pressure is removed and food is available the population will recover in 2 or 3
years. The high resistance of the wild boar to hunting is well illustrated by
population data from a Polish control program (Haber 1961). In 1954 they had
46,500 hogs and removed 11,000 (24 percent). The next year they had 50,000 hogs.

15

la 1955 they removed 40 percent and the population still increased by 1500. In
1956 they killed 33 percent and the population fell by 10,000. In 1958 they re-
moved close to 50 percent and the population remained stable. These data indicate
that not only does a high percentage of the population have to be killed in order
to reduce it, but that the percentage removal effective in stabilizing the
population varies from year to year with the mast crop and weather conditions.
Also, as the population is reduced below carrying capacity, and food limitation
becomes less important the reproductive potential increase*, requiring a
greater percentage of the population be removed each year.

These principles are well understood by European game managers who
cull their herds strongly. Hennig (1963) recommends that at least 50 percent
of the yearling class be removed annually and, that in years of good reproduc-
tion, 80 percent should be killed. Only in cases where an increase in the total
population size is desired or there is an exceptionally poor year for reproduction
should more than 50 percent of the yearlings be allowed to survive. The Germans
also shoot a number of mature animals from the older age classes (6 to 10 years).
These usually constitute about 20 percent of the animals of reproductive age.
Under Henning's scheme removing about 50 percent of the total population is required
to stabilize the age distribution.

At Tellico Wildlife Management Area, where the age classes removed
are not so strictly selected, Richard Conley (personal communication) reported
that about 25 percent of the estimated population can be removed by hunters
each fall without seriously inhibiting the reproduction of the population or re-
ducing it below its carrying capacity. Formal control in Great Smoky Mountains
National Park, therefore, the percent of the population removed annually should
be at least 25 percent and if reduction is desired, it should exceed 50 percent.

In order to apply this information to the Great Smokies, however, we

16

need to know how many hogs there are in the National Park. The standing
estimate in the spring of 19 73 was 50Q animals. This estimate was originally
made in 1959 (Linzey and Linzey 1971). Mike Meyers suggested during the summer
of 19 73 that the estimate be increased to 800 individuals. Unfortunately,
neither of these estimates is from quantitative data. Fox (19 72) believed
500 to be an underestimate and there is evidence to support his suggestion.
First of all this is a lower density per acre than reported for near by Tellico
Wildlife Management Area. Tellico is about a third of the size of the area
presently occupied by hogs in the National Park and has 600 to 800 wild boar

(Richard Conley, personal communication). If the density of hogs in the Park were
equal to that of Tellico the population would be between 1800 and 2400. These
figures may appear high but in other areas of deciduous forest, such as Belowesh
Preserve, there may be 20 hogs per 1000 ha. (Kozlo 1970). The mean for some
large European preserves is 10 to 14 per 1000 ha. and some Far Eastern habitats

may support 30 per 1000 ha. (Heptner and Naumov 1966). Some less favorable
habitats support fewer. The Kaukaschen Nature Preserve has 4 to 8 per 1000 ha.
(Donaurov and Teplov 1938). In agricultural areas where overpopulation instigates
damage to crops, recommended densities vary from 2 to 10 per 1000 ha. (Boback
1955) One should recognize that maintaining a consistantly low density of 6 per
1000 ha. in most deciduous forest habitats requires intensive management through
hunting.

Now suppose 500 hogs was an accurate estimate in 1959, has the Park Service
removed enough hogs to maintain this level? If 25 percent removal on the average
would stabilize the population, the total number of hogs removed would have to
be 125 per year or 1750 over the past 14 years. If 50 percent removal is neces-
sary to stabilize the population, the total number of hogs removed would have to
be 250 hogs a year or 3500 hogs over the past 14 years. Since the Park Service
only removed 522 hogs from 1959-72 (Fox 1972), the official Control Program has not

17

even met the more conservative figure of 1750.

Looking at the situation for 19 74 and 19 75 one can estimate how many
hogs will have to be removed to merely stabilize the population. If, as Mike
Meyers suggests, there are 800 hogs in the Park, and poachers kill 300, the
Park Service needs to remove 100 animals. If poaching is negligible, the Park
Service has to remove 400.- If there are 1800 animals in the Park, the Park Service
needs to remove 600 to 900 hogs. If there are 2400 animals in the Park, the
Control Program should take from 900 to 1200 hogs.

In lieu of a dependable population estimate, a conservative control
program should aim high rather than low. Instead of arbitrarily deciding the
total population is 800 hogs, the Park Service should decide to remove 800 hogs
next year. Since this is about the number taken by the whole control program
over the past decade and a half, the techniques used for control will have to be
revised. An efficient program, which can be maintained through the years with
a minimum of effort, needs to be established immediately before the problem gets
any worse. Furthermore, after the population has been effectively cut back, plans
should be made to maintain hunting pressure on the population since the hogs are
able to recover extremely quickly.
B. Estimating populations.

The more practical aspects of the hog control program can benefit
greatly from ecological research so the two must be pursued together. The first
task is to set up a program for censusing the hog population. In Europe this
is often done in the winter by counting tracks in the snow. The census takers
walk regular transects in selected sections of representative habitats. There
are numerous other standard wildlife censusing techniques that can be tried until
a suitable one is found. For the purposes of hog control, fairly exact estimates
are not as necessary as evaluating relative yearly increases or decreases.

18

In conjunction with the census, information on hog movement into new
areas should be carefully recorded. At present no data is available for the Park,
which shows exactly when the hogs invaded the different watersheds and various
ridgetops, they now occupy. This type of data is easy to collect and has multiple
uses. Quantification of variations in hog population density in areas with
different histories of occupation can provide insight into the hogs' pattern of
resource utilization and the recovery capabilities of some of their food plants.
One can also determine whether the population is remaining constant and occupying
new territory because over grazing is reducing the available food in its old range
or if range extension is paralleled by population expansion. Fadeev (1973)
indicates that when wild boar are expanding their range the density of hogs per
1000 ha. influences the likelihood of movement, the pattern of habitat occupation,
the rate of reproduction, and the resistance of the population to unfavorable
climatic conditions.

Since a control program is useless if the population continues to grow
from year to year, a census is actually the scoreboard which allows management
personnel to assess the success of the control program and to adjust trapping
intensity to population fluctuations. Census data may also be used to construct a
model which will predict population growth under a variety of circumstances.
The most useful variables to quantify are trapping success, mortality from preda-
tors, disease and poachers, the quality of the mast crop and the occurrence of
extreme weather conditions. The census data from the trapping records can provide
the number of offspring per sow each year, the reproductive success of different
age classes and the age structure of the population. By maintaining detailed
records on environmental variables and population structure, it should eventually
be possible to determine the impact of each factor on the hogs reproduction from
year to year. Multivariate techniques of analysis may be used to determine the
importance of individual variables and the presence of synergistic effects.

19

The standard model for determining Rq, the overall reproductive rate
for the population is shown below.

Age Number of animals Age Specific

Class (or females) Survival

N„ 1,

x

-\

Age Specific

Natality

!x mx

mx

0

.00

0

.00

.65

.13

1.55

.35

2.12

.26

2.55

.22

2.13

.04

0 130 1.0

2 26 .20

3 29 .22
4-5 16 .12
6-7 11 .08
8-10 3 .02

1.00
(Data taken from Sablina 1955, and adjusted so that the population is stable.)

Changes in Nx, lx and n^ are all functions of environmental variables.
If there were an outbreak of hog cholera, for instance, Nx and lx would drop
drastically. The magnitude of the change would be greater for younger age classes,
because young animals are more susceptible to the disease. If the mast crop
failed mx should change. In Belowesh, for example, when the mast crop is good,
almost all sows produce young and the average number born is 5.8 per sow with
young. When there is no mast only the older age classes reproduce and the
average number of piglets per sow with young is 3.1. Even in a good year the num-
ber of embryos or young per female is higher in the older age classes. In a
good year 30. 7% of the two year old sows shot during the winter were pregnant as
opposed to 78.1 per cent of the six and seven year olds. The number of embryos
per sow was 4.2 for the two year olds and 6.6 for six to seven year olds.
(Sablina 1955). Thus m^. could actually be treated as a matrix.

20

MAST YEAR

Age
Class

Good

Toor

0
1
2
3
h

0

0

0

0

0

mll

0

0

0

0

m21

m22

m23

m2U

0

m31

m32

m33

m3U

m35

■in

%2

mU3

mUU

mU5

and so forth.

The same is true of lx which is a function of hunting pressure, preda-
tion, disease and food availability. Both lx and mx are density dependent and
are likely to increase as the density of the population decreases. A discrete
value for R0 for any particular year requires a series of vectors which may be
multiplied to obtain an estimate of net increase. Managers would then have a
sound basis for predicting how many hogs of each age class would have to be removed
in order to stabilize or reduce the population. Since different age classes and
the two sexes are not equally important to the reproductive success of the popula-
tion, the question is not only how many hogs are removed but which ones. Using a
model based on age classes, a manager can judge his efficiency in terms of lx mx
and future reproductive potential. A three year old sow may be worth five or ten
piglets.

21

Suggested annual data collection.

A. Hogs

1. Yearly census (possibly in January, by watersheds)

2. Trapping and shooting records by season

a. Age

b. Sex

c. Condition and weight

d. Number of embryos in females

3. Records of natural mortality

4. Poacher kills (This requires asking the right people and acquiring
the trust of localhunting clubs).

5. Movement into new areas, first rooting records.

B. Environment

1. Mast by tree species and elevation

2. Other foods

3. Weather (data already available)

a. Minimum temperatures

b. Monthly mean temperatures and precipatation

c. Ice storms, deep snow, and floods

C. Other species

1. Bear census (The University of Tennessee is already working on this.)

2. Ground nesting bird census (Turkeys and grouse should be easy to do
and a local Audabon group might be asked to help.)

3. Other species particularly deer could be done

4. Continuation of damage surveys in different plant communities.

22

C. Improving the control techniques

Relegating large amounts of manpower to hog control is wasteful unless
the methods used are the most efficient possible. Before launching a full scale
control program the Park Service should first experiment with a variety of
potential improvement in the control techniques presently in use and critically
examine all possibilities.

Fox (1972) found that direct reduction was cheaper than any of the
trapping techniques presently in use in the Park. These results do not, however,
prove that direct reduction is cheaper than all trapping techniques. The effici-
ency of a trapping technique depends on several modifiable components:

(1) Placement of the trap.

(2) Bait or attractant used.

(3) Design of the trap, particularly the gate and the trap.
TRAP PLACEMENT.

As Fox (1972) notes "it would seem that methods of determining a
higher probability of (hog) activity would prove very beneficial in trapping as
well as direct reduction." In Fox's study of 3,325 trap nights there was hog
activity near the traps on only 207 nights and there were captures on only kO
of these. This means that a conscientious manager will have to check the traps
50 to 100 times for each capture. If he could, however, place his trap where hog
activity was guaranteed, he might expect a capture on one out of five nights.
A knowledge of hog food habits and habitat preferences could save a majority of
the man hours spent on the control program. Two attempts in this direction have
already been made, those of Belden (1972) and Scott (1973). Unfortunately, neither
of these studies apply directly to the Park Service problems. Belden provides a
good general outline of the altitudinal movements of the hogs, but his "ocular
estimates" of forest type are too vague to allow effective placement of traps.

23

Scott's (1973) stomach content analysis hardly mentions a genus or species .

A detailed survey of hog rooting in different plant communities is
obviously required. The study should emphasize floristic details, the usefulness
of which can be illustrated by a simple example.

In high elevation beech forest, the rooting pattern of hogs is controllec
by two main factors, the composition of the herbaceous understory and the phenology
of the plants. The hogs prefer a mesic beech understory composed of forbs and
barely touch sites dominated by grasses and sedges. To predict where the hogs will
concentrate above U5OO feet elevation, a manager needs to know not only that the
canopy is composed of beech and buckeye but also that there are carpets of spring
herbs like Claytonia virginica and Erythronium americanum and that the summer florj
includes Laportea, Angelica, Rudbeckia lacinata and Athyrium felix-femina.

Efficient trapping can only be conducted when the hogs are present, whicl
in beech forest, will be for about three weeks between the blooming of Claytonia
virginica and the complete closure of the canopy. After the disappearance of the
vernal flora, hog rooting drops to a low level and continues as an occasional
event through the summer. There is almost no hog activity during winter and early
spring. An efficient trapping or shooting program should concentrate its effort

Scott's (1973) catagories of food items are usually exceedingly general like wood}
roots, green parts of plants or Gramineae. There is no information on where the
hogs were taken. The high proportions of apples and grasses in the summer imply
that many of the hogs were shot in Cades Cove and that a number of natural communi-
ties were severely undersampled. Scott's assessment of the importance of differenl
food items may have little relation to their actual utilization by hogs. One
cannot assess the importance of acorns in the hogs' diet in the fall unless the
percentage of the hogs analysed which were shot in oak forest and the percent of
the total hog population in oak forest at the time is known. Averaged data for the
whole Park is meaningless because there are too many different habitats involved.
Scott (1973) misidentified some of the few taxa he mentions. His Urtica sp., for
instance, is almost certainly Laportea canadensis and his wild yam is probably
Dioscorea batatas not D. villosa. Oddly, he lists Gramineae, but there is not men-
tion of the Cyperaceae or Juncaceae which are so common in woodland situations.

2k

in the month following the full bloom of Claytonia and then move to more produc-
tive sites. Since the density of the hogs in beech forest is very high in late
spring, this is an optimal situation for trapping. Clearly, three weeks worth
of intense trapping effort should offer better return than a more casual program
spaced throughout the year. In the present control program traps are often moved
to sites well after the rooting has started and the traps are then left long after
the hogs have gone.

Locating other good trapping sites and interpreting the temporal patterns
involved is a job for a plant ecologist or a general ecologist with some knowledge
of plant taxonomy. Hog sign is fairly easy to recognize whereas the complex
mosaic of plant communities is difficult to untangle. A field study similar to
Belden's (1972), but more detailed, should be conducted. Data collection could
include:

(1) Site type grazing intensity information.

Whittaker's (1956) study will provide a solid outline for classify-
ing the plant communities. Most of his groups can be subdivided according to the

» t
species composition of the canopy and understory. Releve sampling for plant specie;

should accompany estimates of rooting intensity in the communities most frequently
or intensively utilized by hogs. Accurate species lists should have a high predic-
tive value for trap placement if the exact time of hog rooting is related to
flowering and fruiting times. The same survey can also serve as a record of damage
to plant communities.

(2) Trap success.

Sites which are frequently utilized or intensely rooted should be
recorded on topographic maps. If traps are set up or shooting is conducted, the
relative success at each site should be documented. Accurate lists of the surround-
ing plant species should be compiled. Belden's (1972) and Fox's (1972) studies can
be used as foundation for this.

I IDRADY

25

(3) Collection of potential food items.

When freshly rooted sites are inspected, the investigator should
sift through the remains and pick out fragments of roots, rhizomes, half-eaten
insects, and any other potential food items. Frequently roots can be identified
by comparison with surrounding plants. Rhizomes and tubers can be regenerated.
The time of year and the condition of the plants should be noted. If a certain
species is found in a high proportion of damaged sites it may be an important
food item and can, in any case, serve as an indicator species for predicting hog
activity.

(4) Stomach contents.

The hog stomach contents study should be redone. Not only should
the site of the shooting be recorded but the forest type and plant species pre-
sent should be listed. Again phenological notes about the species in bloom,
in fruit or dying back can be useful. If the most important food items can be
identified to species or genus, then traps can be placed in sites with an abund-
ance of an appropriate species .

(5) Herd size.

Information on the size of herds and the density of the animals
numbers in different habitats can be extracted from sightings, hog tracks and
estimates of rooting intensity. Herd size should vary with season and be at a
maximum during rut. Control techniques are most likely to be effective when the
animals are in large groups.

Management personnel may find that conducting the control program
throughout the year is not as efficient as operating only when the herds are
large or a large portion of the population is gathered in a small area. Further,
during late winter, when food is likely to be in short supply, hogs may be more
easily attracted into heavily baited traps. In January and February, the hogs
will be concentrated at the low elevations. The chances of interference from

26

bears and from Park visitors are much less. January is an excellant time to
catch pregnant sows.

A control program which is keyed to a variety of habitats at differ-
ent times of year will require moving traps frequently or using a large number of
traps and deactivating part of them for long periods. It will also require a man-
ager to coordinate the work.

BAIT

Fox (19 72) indicates that one of the greatest sources of inefficiency
in trapping is the capture of animals other than hogs. In a trapping sequence
which resulted in 40 hog captures the traps were closed 217 times by other animals.
There were 83 captures of raccoons, 6 of bear and 6 of deer. 115 times, the
culprit, probably a bird or small mammal, escaped. Rather than being "hog traps",
the cages collected a random assortment of whatever wildlife was in the vicinity.

As Fox (19 72) mentions, the bait used for trapping in the Park is
normally cracked corn, which is convenient to purchase, light to carry and easy
to scatter. Unfortunately, it is attractive to a wide variety of wildlife in-
cluding grouse, crows, squirrels, deer, bears and raccoons. Diurnal birds and
mammals may relieve a trap of its bait long before the hogs get anywhere near it.
Not only will these smaller animals sometimes trip the gate and then flee, but
they can easily eat most of the bait and leave the trap open and empty.

In order to improve trapping efficiency, a more selective bait should
be used. Field observations indicate that hogs can locate food several inches
underground. Burying the bait will exclude crows, grouse, turkeys and deer and
should slow down the raccoons. Some simple experiments with penned hogs can pro-
vide information on optimal bait sizes, depths, and patterns of dispersal.

New bait items could also improve trapping efficiency. The hogs in the
Park are incredibly adept at locating patches of Pi os core a batatas, which implies

27

potatoes or yams might be good bait. Makin (1971) points to potatoes as the
main source of agricultural damage by hogs; it is well known that wild boar
often travel long distances, more than 10 or 15 kilometers, to raid potato fields.
Tubers keep well when buried, and will remain in good condition until discovered
by the hogs. The size and weight of potatoes make them difficult to transport,
but the same properties make it nearly impossible for small mammals to remove them
from the traps.

Some observations on the normal food habits of the wild boar may provide
clues to other successful baits. The hogs preferences for certain foods at certain
times of year indicate they respond to chemical changes in the plants. The hogs
are best able to find the bulbs of Turk's- cap lily when the stems are dying back
for the season. This implies the hogs may be able to smell the sugars involved
in moving nutrients to the bulbs. Another example is found in Bromlei (1964)
who mentions that hogs only eat winter horsetail in winter. Bromlei attributes
this to the presence of "soluble carbohydrates" after frost. A few experiments
with penned hogs on their preferences for different sugars and starches, in
dry, crystalline or dissolved forms could provide a highly attractive bait
that pigs can locate easily.

Aside from food, Fox (19 72) experimented with using a sow in heat for
bait. This use of sexual attractants for trapping hogs has potential but will
require some modification. First, sows are heavy and hard to handle so, the use
of a pure chemical substance isolated from the animal is desirable. This might
be achieved by collecting urineor by washing the external gentilia with the right
solvent after injecting the sow with hormones. If the proper volatile chemical
can be gotten in solution then the whole thing can be used for bait by allowing
it to slowly evaporate. Second, certain times of year are likely to be more
profitable trapping with this technique than others. If, for instance, pheromones

28

or females in esterous and food were used together during the rutting season, when
the hogs are in large herds, both males and females might be captured. When, for
public relations purposes, providing hogs for stocking at Tellico or other areas
seems useful, sows in esterous or pheromones might be used to round up a few
males immediately before the hunts. Chemical attractants will require experi-
mentation and probably some laboratory work.

Baits and attractants can be used in conjunction with reduction
techniques other than trapping. A selective bait is necessary for administering
an ti- fertility agents or poisons. Baiting could also potentially improve the
efficiency of direct reduction.

TRAP DESIGN

Another major limitation on the success of the present trapping program
is the size of the traps employed. All of the "portable traps" are individual
traps and the four group traps are permanently placed. There are no group traps
throughout most of the hogs' range. Since hogs often travel in herds, the
individual traps only capture a small percentage of the animals near the trap.
Direct reduction also makes no use of the size of the herds.

According to Donarov and Teplov (1938), herd size nay be between 1 iand
40 animals. The average varies from month to month from 3.0 to 10.2 animals.
The latter figure is for rutting season. The average number of wild boar in 273
individual sightings was 5.9 for the year. A corral trap should, therefore, be the
most efficient. Because of the rough topography of the Southern Appalachians, the
elements of a trap have to be light and easy to assemble. A variety of fencing mater:
including barbed wire, and electric fence could be tried. Some quick trials in the
field and with penned wild hogs will provide the necessary information about fence h<
wire spacing, wire tension and the usefulness of electric current. Electric fence do<
not always work well to exclude hogs from fields and forest plantations (Cointat 195!
Used in combination with other types of fencing materials, and used with a stronger

29

than normal electric charge, electric fence might lower the weight of the other
materials needed. Snethlage (1967) suggests two different hog proof fence designs.
The first is made of mesh fencing or regular hog fence. This fence should begin
at ground level and stand about a meter high. Snethlage puts a thick pole above
the mesh but an electrified wire might serve the same purpose.

The second design is about the same height. Near the ground, 4 strands
of barbed wire are strung 10 to 20 cm. apart. Two more strands, with slightly
wider spacing (30 cm.), are strung above. The strands are then fastened together
by more wire tied perpendicularly to the ground. Depressions, creating gaps under
the fence where the hogs could crawl out of the enclosure, can be closed with
stakes. A slat or pole placed lengthwise along the bottom of the fence will serve
the same purpose.

In forests where the trees are narrow in diameter, the trunks may
serve as fence posts. A piece of wood should be inserted between the wire and the
tree to prevent damage to the bark. Supplemental fence posts can be used as
necessary. According to Snethlage (1967) the posts or trees should not be more
than 6 meters apart. The corral does not have to be regular in shape and the
design should reflect local topographic patterns. Sturdiness is more important
than neatness.

Since many of the best trapping areas are not easily accessible, the
lighter the materials, the better. The trap has to be able to hold a mature
boar, of course, but cyclone fencing is probably not necessary. If all the
materials could be horse packed or back packed, traps could be constructed in
areas which have the heaviest concentrations of hogs.

One of the greatest shortcomings of the group traps already in use in
the Park is their failure to produce more multiple captures than the smaller port-
able traps. The difficulty is simply that the first animal in the trap springs
the slam gate. There are several possible solutions which will require some ex-

30

periraentation. One possibility is a multiple trap. The animals have to knock
over, a step on or uproot more than one trigger mechanism. The triggers could
be set up near scattered concentrations of bait. Another possibility is a delayed
action trigger. The first or second hog in the trap hits the trigger but several
minutes elapse before the gate slams down. This provides time for more individuals
to wander into the trap before it shuts. These techniques will require large amounts
of bait in the traps to keep the hogs from eating all the bait and leaving before
the trap shuts. A one way sliding gate or turnstile is also worth trying with
heavily baited traps.

OTHER TECHNIQUES.

Shooting has advantages when the hogs are widely scattered, but a care-
fully conducted trapping program should be superior when the hogs are in herds.
The success of a shooting program can be improved by using ecological data to
locate concentrations of animals and by baiting. Driving or using dogs can also
increase the number of encounters in direct reduction.

Poisoning or sterilizing with chemical agents requires extremely speci-
fic baits. Although both techniques are worth considering, they will require a
more extensive food habits study than is presently available.

PHILOSOPHICAL PROBLEMS.

Some of the most severe limitations on the Control Program are neither
technical nor scientific, but are a function of the point of view from which the
work is conducted. Almost all the hog trapping has been done along jeep roads,
for instance. Unfortunately, many of the smaller watersheds can only be reached
on foot or horseback and many of the best potential trapping sites are more
than half a mile from the nearest road. Although there are good reasons for
conducting intensive control around Cades Cove where the traps are easy to check,

31

some of the work will have to be done in the back country, out on the ridges
and down in the valleys without access roads.

Since there are more problems on the highways and in the camp-
grounds than the staff can handle, the back country ranger and pack horse have
all but disappeared in the Great Smoky Mountains. The hogs have to be met on
their own ground, however, and the problem is not concentrated in convenient places.
The "inaccessibility" of the back country is the usual reason given for restrict-
ing trapping to sites near roads, but the difficulty can be overcome by hiking,
horseback riding, packing heavy equipment, working long days and staying out all
night on the trail.

A second similar limitation on the control program is the lack of biolo-
gical staff in the Park. Most of what little scientific work is being done in the
Park is falling into a vaccuum. Central coordination of projects is lacking and
a majority of the data obtained is never used. The ranger in charge of management
has too many other responsibilities, such as fire control, to devote any time
to building an effective research program. The present situation is wasting time
and resources. The Park Service needs to establish a better bridge between
research and management.

The Park now has a number of chronic ecological problems, such as the
hogs and the accelerating woody plant invasion of the grass balds. Eventually
something will have to be done since these afflictions show no signs of healing
themselves. The Park has considered making room for a biologist but has put off
actually getting one. In the meantime, wildf lower areas are being severely damaged,
and the hog problem is spreading to include the whole Park. In fact, the hog pop-
ulation is now large enough so that it is unlikely one or two additional staff
members will be able to bring the species under control. A biologist could
actually be most useful in soliciting and coordinating help from outside agencies
and universities.

32

The question is essentially one of land stewardship and a sense of
responsibility for the native flora and faura. The Park needs ecological
watchmen who will recognize and solve the problems as they arise.
III. Conclusion.

The Park Service needs to take a new direction in ecological management
in Great Smoky Mountains National Park. The European wild boar population has
caused extensive damage and is now large enough to warrant full time attention
from the management staff. Even if various universities and graduate students
assist in the project, central coordination must come from within the Park. It
may already be impossible to exterminate the wild boar within the Park, but
this should not become an excuse for abandoning control altogether. In order
to protect the native flora and fauna the hog population has to be kept low and
stable. If the boar are allowed free run of the Park they will surely take it.

An efficient control program cannot be disconnected from natural history and
basic ecologic research. A good field ecologist or wildlife manager will, of
course, realize immediately that most of the necessary information on life history
casually mentioned in this paper can be extremely difficult to obtain. In spite
of this the Europeans have gathered volumes of relevant population data and there
is no reason to believe, that the same thing cannot be accomplished in the
Smokies. It is a matter of time, money, and most important, finding the right
people to do the work.

The control program must favor imagination and experimentation until more
efficient methods of hog control are developed. The suggestions presented in
this paper are not offered as a final solution but instead are to be treated as
ideas which can be tried and evaluated. If they prove impractical or inefficient
they should be modified, or abandoned and replaced by something better.

Effective management must be dynamic, bending and adjusting to each idio-
syncrasy of each species concerned,. Park policies have to evolve with changes in the

33

populations and the intensity of the disturbance. None of the Park's present
management problems have easy or clear cut solutions, but none of them are com-
pletely insoluble. I am convinced that most of the difficulties can be resolved
by hard work, good science, and common sense.

34

l i EKATURE ClTEi)

Beem-'Uif Larry rfugen< < 1971. Seasonal food habits ot the

blacK oear (Ursus d^rj-carius) in the Smojcy Mountains of

Tennessee and North Carolina. M.S. Thesis. The University of
Tennessee. 62 pp.

Belden, h.C. 1972. Rootmq and wallowing activities of the
European Wild Hoy (^u^i £££2££) in trte mountains ot East
Tennessee. M.S. Thesis. The University of lennessee. 68 pp.

Bjerke, S. 1957. Nogle traek af de sydsxandinaviske
lovskoves udu~jkling qennem de sidste arhundreder. Dansx.
dendrol. Algskv. No. 4 :J7J-413.

Bjerke, S. 1959. Om svin og skov. Dans* sKovforen. Tidsskr.
4 4(10) : 529-40.

Soback, A.«l. 1957. Das Schwarzwilu. Neumann Verlag:
Leipzig. 141 pp.

Bratton, S.P. 1974. The effect of the European Wild boar
(2Ji£ £9.±2±£ L«) on the high-ele vation vernal flora in Great
SmoKy Mountains National Park. Manuscript. Cornell

35

University. 30 pp.

Briedermann, L- 1967. Die Nahiunqs Komponenten des
Schwarzwildes (Sus s. scrota 1959) in der Mit telouropaischen
K ulturiandschaf t . Trans. of the Vllth Convjr. or the Inter.
Union of Game Biologists: 207-213.

Briedermann, L. 196d. Die biologische und forstiiche
Bedeutung des «'i ldschwoiuos in Wirtschar tswald. Arch.
Forstves. 17 (9) : 943-967.

Bromlei, G.F. 1964. Ussuniskii Kaban. Izdatel'stuo "NauXa",
Moskva. 107 pp.

Cabon, K. 1957. Das Massensterben von Wildsch weinen ira
Naturstaatspark von Bialoviezc im Winter 1955/56. Acta
Theriol. , Bialowiezc 2(4): 71-82.

Campbell, C.C., «I.F. Hutson and A.J. .Sharp. 1962. Great
Smoky Mountains Wildf lowers. The University of Tennessee
Press, Knoxville. 112 pp.

Cointat, M. 1953. Cloture electrique en foret. Rev. For.
Franc. 5(11): 15-16.

36

Conley, K.H., V.G. Henry and G.H. Match*e. 1972. European
Hog Research Project H-34. Tennessee Game ana Fish
Commission. Nashville. 259 pp.

Donaurov, S.S. and V.P. Teplov. 1938. Kaban v kavkazskom
ZapovedniJce. Trudy Kabkazskogo Gosudarst vennogo Zapovednika.
1:191-226.

Faaeev, E.V- 1973. Dinamika chslennosti jcabana (Sus §crofa)
V Evropeiskoi Hossii. Zool. Zh. 52(8): 1214-1219.

Fernald, Merntt Syndon. 1950. Gray's Manual of Botany:
Eigth (Centenial) Edition. American Book Company: New York
1632 pp.

Fox, J.R. 1972. An evaluation of control techniques for the
European tfild Hog (Sus scrofa) in the Great Smoky Mountains
National Park of Tennessee. M.S. Thesis. The University of
Tennessee. 76 pp.

Gavrin, V.F. and C.C. bonaurov. 1954. Volk v Belovezhskoi
Pushche. Zool. Zh. 36 (4) : 904-924.

Haber, A.
108:74-76.

1961,

Le sanglier en Pologne. Terre et Vie.

37

Hennig, K« 1963. Schwarzwildhege, Schwdrzwild jagd.
Landbuch-Ver lag GMBH, Hanover. 116 pp.

Hennig, R. 1972. Das Sch warzwild. Landbuch-Verlag GMBH,
Hannover. b8 pp.

Henry, V.G. ana R. H. Conley. 1972. Fall foods ot the
European Wild Hogs in the Southern Appalachins. J. Wildl.
Mgmt. 36 (3) :854-86Q.

Heptner, V.G. and N. P. Naumov. 1966. Div Saugetiere der
Sowjetunion. VEB Gustav Fischer Verlag, Jena. 939 pp.

liottraan, Harold L. 19b/. Check list ot vascular plants of
the Great Smoky Mountains. Castanea 29:1-45.

Janda, M. 1958. Die Nahrung des Sch warzwildes Ira
M ittelgebirgsgebiet von Stiavnica. Saugetier Kundl. Mitt.
4 (2) :67-72.

Kerschagi, w. 19b5. Wild Krankhei ten . Os terreichischer Jagd
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Konailitsm, A. A. and A.I. Dulitsii.

1972.

38

i oakklimatiza tsii suin'i dikoi (Bus scroU L.) v Krymu
Vestnik Zoologii: 6 (1): 38-44.

Kozlo, P.G. 1970. Faktory, opredely ayushchie dinamiku
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Zool. Zh. 49: 422-430.

Linzey, A.V. and D.w. Linzey. 1971. Mammals of Great SmoK.y
Mountains National Park. The University or Tennessee Press,
Knoxvilie. 114 pp.

Lo}inov, V.V. 1936. Novye dannye k poznaniyu biologii
Kaukazskogo Kaban (Sus scrota attila Thomas) . Bull. Soc. Nat.
Moscow, Sect. Biol. 45:10-21.

Mackin, R. 1970. Dynamics of Damage caused by wild boar to
different agriculture crops. Acta Theriologica.
15(27) :447-45B.

Matschke, G.H. 1967 (1964). The influence of oak mast on
European wild hog reproduction. Proc. Southeastern Assoc.
Game and Fish Commissioners Conf. 18: 35-39.

Muller-Using, D. 1960. Grobtier und Kulturlandschatt lm
mitteleuropaischen Raum. M usterschmidt Verlac: Gottingen. 157
pp.

39

Niethammer, G. 1963. Di^ Einburgerung von Saugentieren und
Vo^lea in Europa. Verlag Paul Parey. Hamburg 319 pp.

Peterson, R.T. and M. McKenny. 196B. A Field Guide to
dildflowers of Northeastern and North-central North America.
Houghton Mifflin Co., aoston. 420 pp.

Pfetier, P. 1961. L'ecologie du sanglier en Asie centrale
d'Apres les recherches d'A.A. Sloudsky. Terre et Vie.
10a: 368-372.

Radford, A. t. , H.E. Ahles, and C.R. Bell. 1968. Manual of
th« Vascular Flora of the Carolinas. The University of North
Carolina Press. Chapel Hill. 1183 pp.

Rakov, N.V. 1966. Ob osobennostyakh sosushchestvovaniya
Kaban, burogo i chepnogo medvedei v Amuro - Ussuriiskom Krae.
Zool. Zh. 4b (4) :617-618.

HaKov, N.V. 1970. 0 fakorakh smertnosti kabana i ego
vzai mootnosheniy akn S Khshchnikami v Priamur'e. Zool. Zh.
49(8) : 1220-1228.

Sablina, T.b. 1955. Kopytnye Belovezhskoi Pushchi.

40

Akademiia Nauk SRK. Institut Morfologii Zhivotnykh. 15:1-191.

Schulze. 1965. Die Krankheiten des Wildes. F.C. Mayer
Verlag. Munchen Solin. 214 pp.

Scott, CD. 1973. Seasonal food habits of European wild hogs
(Su§ scrofa) in the Great Smoky Mountains National Park. M.S.
Thesis. University of Tennessee, 54 pp.

Severtsov, S.A. and T.b. Sablina. 1953. 01en*, kosulya i
kaban v Zapovedhike Belovezhskaya Pushcha. Akademiia Nauk
SSSR. Institut Morfologii Zhivotnykh. 9:140-205.

SludsKii, A. A. 1956. Kaban: Morfologiya, Ekologiya,
Khozyaistvennoe i Epizootologicheskoe Znachenie, Proiaysel.
Izdatel'svo Akademii Nauk Kazakhskoi SSK, Alma-Ata. 219 pp.

Snethlage, K. 1967. Das Schwarzwild. Verlag Paul Pareg,
Hamburg. 215 pp.

Snethlage, K and K.H. Snethlage. 1966. Schwarzw iidf ibel.
Verlag Paul Parey, Hamburg. 29 pp.

Spiecker, von. D. 1969. Verlauf und Ausbreitung der
Schweinepest (Pesti suum) in der Eifel in den Jahren 1963 und

41

1964. Z. Jagdwiss. 15: 144-151.

Stegeiaan, L.C. 193d. The European wild ooar in the Cherokee
National Forest, Tennessee. J. Mammal. 19 (3) : 279-290.

StupKa, Artnur. 1960. Great Smoky Mountains National Park,
Natural History Handbook, Series No. 5. U.S. Government
Printing Office, Washington, D.C. 75 pp.

Stupka, A. 1963. Notes on the Birds of Great Smoky Mountains
National Park. The University of Tennessee Press, Knoxville.
242 pp.

VoLeshchagin, N. K. 1967. The Mammals or" the Caucasus: A
History ot the Evolution of the Fauna. U.S. Department of
Commerce. Springfield, Va. 816 pp.

Weidenmuller, H. 1964. Fibel der Wild Krankheiten. Verlag
Eugen Ulmer. Stuttgart. 116 pp.

Wetzel, R. and W. Rieck. 1962. Krankheiten des Wildes.
Verlag Paul Parey, Hamburg. 224 pp.

Whittaker, R.H. 1956. Vegetation of the Great Smoky
Mountains. Ecol. Monogr. 26: 1-80.

k2

Williamson, M.J. and M.R. Pelton. 197 1. New design for a
laLye portable mammal trap. Trans. Ann. Conl. SE Assoc. or
Game and Fish Comm. 25; J 15-322.

ADDITIONAL REFERENCES

General:

vSevertsov, S. A. and T. B. Sablina, 1953. Olen' , Kosulya Kabum V. Zapoveduite
Belovezhskaya Pushcha. Izdatel'svo Akademiaa Nauk SSSR. Institute Morfologii
Zhivotuykl, 9:140-205.

Jones, Perry. 1972. The European wild boar in North Carolina. North Carolina
Wildlife Resources Commission. Raleigh, N.C. 27 pp.

Pine, D.S. and G.L. Gerdes. 1973. Wild pigs in Monterey County, California.
California Fish and Game 59(2): 126-137.

Haber, A. 1969 Dzik. Panstwowe Wydawnicto Rolnicze i Lesne. Waszawa. 216 pp.

Oloff, H. 1951. Zur Biologic and Okologie des Wi ldschweines . Beitrage zur
Tierkunde and Tierzucht. Band 2. 95 pp.

Rakov, N.V. 1956. Nekotorye osobennosti uslobpv sushchectvovanpya kabana na
Spkhote- Aline. Biolleten M. O-va. Isp. Pripody, Otd. Biologii. T. LXI (1)

13 22.

Hanson, R. P. and L. Karstad. 1959. Feral swine in the southeastern united
States. J. Wildl. Mgmt. 23(1): 64- 75.

Shaw, A.C. 1941. The European wild hog in America. Trans. N. Amer. Wildl.
Conf. 5:436-441.

Behavior:

Fradrich, H. 1974. A comparison of behavior in the Suidae. In The Behavior

of Ungulates and Its Relation to Management, pp. 133-143.

Fradrich, H. 1967. Das Verhalten der Schweine (Suidae, Tasas suidae) and
Flusspferde (Hippopotami dae) . Hdb. d. Zool. 10(26) :l-44.

Briedermann, L. 1973 Ermittlungen zur Aktivitatsperiodik des Mitteleuropasschen
Wildschweines. Zool. Garten i. Dr. b.

Damage and food habits :

Spatz, G. and D. Mueller-Dombois. 1972. Succession patterns after pig digging
in grassland communities on Mauna Loa, Hawaii. Island Ecosystems IBP,
Technical Report No. 15. 44 pp.

Zappe, E. 1958. Bedeutung des Schwarzwildes Schadinsektengradation in Walde.
Forst and Jagd 8: 33-34.

Krammer, R. J. 1971. Hawaii Land Mammals. Charles E. Tuttle Co., Rutland,
Vermont. 347 pp. (see chapter on pig food habits) .

Henry, V. G. Predation on dummy nests of ground nesting birds in the
Southern Appalachians. J. Wildl. Manage. 33(1) :169-172.

Matschke, G. H. 1965. Predation by European wild hogs on dummy nests of
ground- dwelling birds. Trans. Ann. Conf. S.E. Assoc, of Game and Fish Comm.
20:74-84.

Matschke, G. H. 1964. The influence of oak mast on European wild hog
production. Trans. Ann. Conf. S.E. Association Game and Fish Comm. 19:154-156.

Matschke, G. H., K. M. Barht and R. L. Murphree. 1973. Digestion of crude
protein in white oak acorns by European wild hogs and Pitman-Moore minature
hogs. -J. Term. Acad. Sci. 48(3): 85-86.

Bratton, S.P. 1975. The effect the European wild boar on Gray Beech Forest
in the Great Smoky Mountains. Ecology 56(6).

Howe, T. and S. P. Bratton. Manuscript. Winter rooting activity of the
European wild boar.. 18 pp.

Wodzicki, K. A. Introduced Mammals of New Zealand. Department of Scientific
and Industrial Research Bulletin No. 98 (see pages 227 to 240).

Howard, W. E. 1964. Introduced browsing mammals and habitat stability in
New Zealand. J. Wildl. Manage. 28(3): 421-430.

Management :

Taber, R. 1961. Wildlife administration and management in Poland. J. Wildl.

Manage. 25(4) : 353-363.

Webb, W. L. 1960. Forest wildlife management in Germany. J. Wildl. Manage.
24 (2): 147-161.

Zurowski, W. and M. Sakowicz. 1965. Effects of succinylcholine chloride
on wild boars. J. Wildl. Manage. 29(3) :626-629.

Henry, V. G. and G. H. Matschke. 1968. Immobilizing trapped European wild
hogs with Cap- Chur-Barb. J. Wildl. Manage. 32(4) :970-972.

Matschke, G. H. 1962. Trapping and handling European wild hogs. Trans. Ann.
Conf. S. E. Assoc, of Game and Fish Comm. 16:21-24.

Matschke, G. H. and V. G. Henry. 1969. Immobilizing European wild hogs with
succinylcholine chloride. J. Wildl. Manage. 33(4) :1039-1041.

Munzel, E. 1971. Der Saupark bei Springe. Stuttgart: DRW- Verlag. 147 pp.

Henry, V. G. 1966. European wild hog hunting season recommendations based
on reproductive data. Trans. Ann. Conf. S.E. Assoc, of Game and Fish Comm.
20:139-145.

Movements :

Kurz, C. J. and P. L. Marchinton. 1972. Radio telemetry studies of feral hogs

in South Carolina. J. Wildl. Manage. 36(4) : 1240-1250.

Matschke, G. H. and J. P. Hardister. 1966. Movement of transplanted European
wild boars in North Carolina and Tennessee. Trans. Ann. Conf. S.E. Assoc, of
Game and Fish Comm. 20:74-84.

Fadeev, E. V. 1970. Estestbennoe i iskusstvennoe rasselenie kabana v
Evropeiskoi chasti RSFSR. Biologicheskie Nauki 1:28-34.

Fadeev, E. V. 1973. K ekologii kabana tsentralnoi Rossii. Vest. Mosk. Univer.
Biol. 5:20-28.

Chemjavskaya, S. I. 1956. Sezonne rasmeshchenie i kochevki dikikh ko-pynykh
i medvedya b raione Kavkazskogo Zapovednika v svyazi s raspredeleniem urozhaya
plodov fruktarnikov i orekhonosov. Biol. M. 0-VA Isp. Prirody, Otd.
Biologii. LXI(4):7-21.

Nasimovich, A. A. 1955. Rol Rezhima Snezhogo Iokpova V Zhizni Kopytnykh
Zhivotnykh na Territorii SSSR. Izdatelstvo Akademii Hauk SSR. Mosckva.
(Chapter on wild boar 288-297).

Morphology and reproduction:

Briedermann, Lutz. 1970. Zum Korper - and Organwachstum des Wildschweines

in der Deutschen Demokratischen Republik. Arch. Forstwes. 19(4) :401-420.

Briedermann, Lutz. 1971. Zur Reproduction des Schwarzwildes in der Deutschen
Demokratischen Republik. Tag. Ber. dt. Akad. Landwirtsch. 113:169-186.

Cabon, K. 1959. Problem der Alterbestimmung beim Wildschwein (Sus scrofa L.)
nach der Methode von Dub. Acta Theriol. 3(8) :113-124.

Cabon, K. 1958. Untersuchungen uber die Schadelvariabilitat des Wildschweines,
Sus scrofa L. aus Nordostpolen. Acta Theriol. 2(6) :107-139.

Duncan, R. W. 1974. Reproductive biology of the European wild hog (Sus scrofa)
in the Great Smoky Mountains of Tennessee. M. S. Thesis, University of
Tennessee, Knoxville. 95 pp.

Henson, T. M. 1975. Age determination and age structure of the European
wild hog (Sus scrofa) . M. S. Thesis, University of Tennessee, Knoxville.
58 pp.

Henry, V. G. 1968. Length of the estrous cycle and gestation in European
wild hogs. J. Wildl. Manage. 32(2) :406-408.

Henry, V. G. 1968. Fetal development in European wild hogs, J. Wildl. Manage.
32(4):966-970.

Henry, V. G. 1969. Estimating whole weights from dresses weights for
European wild hogs. J. Wildl. Manage. 33(1) : 22-225.

Henry, V. G. 1969. Detecting the presence of European wild hogs. J. Tenn.
Acad. Sci. 44(4): 20-23.

Matschke, G. H. 1963. An eye lens-nutrition study of penned European wild
hogs. Trans. Ann. Conf. S.E. Assoc, of Game and Fish Comm. 17:20-27.

Matschke, G. H. 1967. Aging European wild hogs by dentition. J. Wildl. Manage.
31(1):109-113.

Morphology continued:

Williamson, M. J. 1972. Some hematological and serum biochemical parameters
of European wild hogs (Sus scrofa) . M. S. Thesis, University of Tennessee,
Knoxville. 44 pp.

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